Fuel supply system for aircraft



R. E. GREY ETAL ,4 62

FUEL SUPPLY SYSTEM FOR AIRCRAFT April 27, 1948.

Filed Feb. 16, 1942 2 Sheets-Sheet 1 /NL/Nrog.9 9 449 f. Gee-v April 27, 1948, R. E. GREY ETAL I 2,440,262

FUEL SUPPLY SYSTEM FOR AIRCRAFT Filed Feb. 16, 1942 2 Sheets-Sheet 2 FIG. 2.

P44 PH 5 GREY Eon 420 #7. 440

Patented Apr. 27, 1948 UNITED STATES PATENT OFFICE FUEL SUPPLY SYSTEM FOR AIRCRAFT Ralph E. Grey and Edward M. Gavin,

Osborn, Ohio (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) 15 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to us of any royalty thereon.

This invention relates to an improved fuel system for aircraft and more particularly to a fuel system suitable for use on large aircraft having a plurality of engines and a plurality of fuel reservoirs for supplying those engines with fuel. In installations of this nature it is customary to provide each engine with its own individual fuel tank from which it normally receives its supply of fuel. It is desirable, however, that if necessary, the fuel from a particular tank may be supplied to engines other than its own. For example, if one of the engines should become disabled for any reason, the fuel in its tank might be needed for the continued operation of the remaining engines. Or, in the event that a reserve tank be carried in the aircraft, it is, of course, necessary that the fuel therein be made available to any one or all of the engines on the craft. Another desideratum of any fuel supply system is that it be possible to transfer fuel from any one of the tanks to any other tank or tanks. For instance if a leak occurs in one of the tanks either from natural causes or as the result of enemy gunfire, it becomes desirable to transfer the fuel from the leaking tank into another tank on the aircraft both for the purpose of conserving fuel and also to eliminate the fire hazard resulting from the escaping gasoline. A fuel transfer system is also advantageous from the standpoint of balancing the load carried by the aircraft, it being possible with such a system to move the fuel from one tank to another so as to keep the center of gravity of the aircraft in its proper location. The improved fuel system which forms the subject of our invention provides both for the cross-feeding of fuel between engines and also for the transfer of fuel from one tank to another. It also constitutes what we believe to be the simplest, lightest and most expeditious system of this type yet devised.

We acknowledge it to be old and well known in the art of fuel systems for multiengined craft to provide a separate fuel tank for each of the engines together with a cross-feed fuel line for enabling the fuel to be delivered from one of the tanks to an engine or engines other than its own, An arrangement such as this is shown on page 60 of a book entitled A. M. Fuel Systems for Aircraft, written by Basile Demtchenko and published by Gauthier Villars, 55 Quai des Grands-Augustins, Paris, in 1938. In this system each engine is provided with its own separate tank and with a short, direct tank-to-engine fuel line for conveying the fuel from the tank to the engine. A cross-feed fuel line joins together all of the tank-to-engine lines andfuel cocks are provided in the cross-feed line between the engine-tank units in orderthatthe units may be separated by the closing of the cocks. Cocks are also provided in the tank-to-engine fuel lines at a point intermediate the tank and cross-feed line to permit isolation of each tank from the rest of the system. This arrangementrsuffers from several disadvantages, however, one being that when it is desired to cut out one of the tanks and feed its engine from one of the other tanks, it is necessary to close the tank cock and to open the cock in the cross-feed line. Thus it is necessary to operate two cocks to effect the desired result. In our improved system, however, the operation of a single valve or cock located at the intersection of the tank-to-engine and cross-feed lines serves to simultaneously isolate the tank and also to connect its engine to the-cross-feed line.

Another disadvantage of the system disclosed by Demtchenko lies in the fact that the crossfeeding of fuel is restricted to adjacent engines; that is, in a four-engined aircraft it is impossible to supply engines I and 3 from the tank of engine I." Engine 2 must also be included with engines I and 3 although under certain circumstances this may not be desirable. According to our invention a three-way valve or cock is provided at each juncture of the cross-feed line with a tankto-engine line thus making it possible to supply non-adjacent engines with fuel from the tank of one of them without bringing in the intermediate engines, It is also possible with our new system to connect one or more reserve tanks to the crossf'eed line by a simple T fitting whereby any selected engine or engines may be supplied with fuel from the reserve tanks by simply setting the valve of the engine or engines in such a position as to connect the latter with the cross-feed line.

Another important feature of our improved system resides in the use of booster pumps located adjacent to each of the fuel tanks for transferring fuel from one tank to the other. While We are aware that the use of booster pumps per se is old, we believe that we are the first to use these pumps for a dual purpose, viz., the lifting of fuel to the engine pumps and also the pumping of fuel from one tank to another in fuel transfer operations. By setting the valves of the tanks between which fuel is to be transferred to their cross-feed positions, and then starting the 3 booster pump of the tank from which fuel is to be drawn and stopping the booster pump of the tank to which fuel is to be delivered, a transfer of fuel between the tanks may be effected. Inasmuch as the booster pumps are of the centrifugal type no difficulty. is encountered invpassing fuel through the pump which is at rest. Thus the same pumps, valves and fuel lines, which are used for delivering fuel to the engines both directly and also by means of the cross-feed line are also used for transferring f'ueli-f'r'omone tank to the other. No additional equipment is neces-..

sary for accomplishing this function as is the'casein all of the present systems with which we are familiar.

It is therefore evident from the above that the fuel system which forms the subject of our invention is an extremely fiexible,,one, ri-t being possible to route the fuel from practically, any point in the system to any other point therein. At the same time'the system is. simple in nature and light inv Weight, thelen-gth ofthe fuellines beingconsiderably shortened and, the number, of

valves, cocks, remote controls, etc., being greatly reduced in number. Asa result of the shortening of. the lines in our system itbeco-mes feasible to usefiexible bulletproof hose in place of the thin-walled alu-minum tubing customarily used for fuel;lines.. Hitherto it has always been imI- practical: to use thebulletproof hose in place of the aluminum tubing due to. the greater weight of the former, The use of} flexible hose greatly simplifiesthe. installation and maintenance of the :lines and-also reducesv the. possibility or failure: due to vibrational fatigue. Thesimplificationtof the system: and the reduction 'iri the number of fittings and controlssed; therein also greatly; reduces; the vulnerability: of, the system being-;fewer lines andfewer vital elements interposed-in thoselines for-bullets to-hit.,

Accordin lm; the principal; object of our invention is; to;preyide;anfimproyed fuel system ,mu ti ns ned ai e a-ft-v n Whi b h: ro feedin and trans errin -offuel marleeff d nd-which; atzth'es ame time, is x rem ly m l in natureanclg is; comprisedtofi relativelyfew parts Another obj eat of: our inventiongisg to' provide a fuel system. of; the type: described above in.

which: a three-Way; valyejq'ori cocktisi located at the intersection. of each:tank-to-,eng.ine fuel; line withthe. cross-.feedi fuel :line;

and at the. same time simpllfieszritu A furtherv object ofiour' invention is to provide a. novel fuel-transfer system in. which. a booster pump located; adjacent tothebottom of each fuel tank maybe used to draw fuel out. of. the

tank; pump it. through the cross-feed: fuel line;

and deliver it into: any selected? one: of: the remaining tanksv Still. a further object: ofour invention-is to provide. a reserve; fuel tank which is connected through. a booster pump. to the cross-feed: line. By means of' the above mentionedu three-way valves the fuel in the reserve tankmay be fed engineby 'means of. a direct fuel line extending This arrangement greatly; increases". the usefulness-z. of the) system.

4 therebetween. Interposed in each of these fuel lines is a three-way valve or cock which is remotely controlled from the dashboard of the aircraft. A cross-feed fuel line is provided which communicates With one of the ports on each of the valves and also with the fuel line leading to the: reserve tank or tanks. as the valves are operated by a remote control arrangement, these valves may be placed in the wings of the aircraft so as to enable the tankto-engine fuel'. lines to be made as short as possible. A centrifugal type of booster pump is located in or adjacent to the bottom of each fuel tank for the purpose of supplying fuel from said whichisselected for supplying. the fuel to the engines is ordinarily utilized to deliver the fuel through the cross-feed line under pressure. However; since each of the engines is provided witliits own-fuel pump it. is'not essential that the booster pump be utilized for. the delivery offuel to the engines. In the event thatthe booster pump becomes disabledthe engines will. still be able to draw up fuel from. the tank since the booster pump is of a centrifugal type and fuel may flow therethrough even though the pump is notope ati'ng. In this case the previously mentionedv engine pumps will beable-todraw fuel fromthetank, up toutheir respective engines provided that-the aircraftvis not flying at-an excessive altitude.- For high altitude flight. the operation-"ofthe booster pump is essential in order to prevent a vapor lock from'occurring in.

pump forthe: tank to which the fuel is to [be delivered must be stoppeolso as to permit the fuel=to flow-therethrough andintothe tank.

From the above it will be apparent that we havedevised a fuelsystem which combines flexibility; of operation with extreme simplicity of construction. Itshould also be noted that our system will accomplish" allot the results obtainable with the older systems and that it accomplishes these-results with muchfewer parts and with much shorter fuel lines.

A more; detaileddescription of a; typical fuel system-embodying; the principals: of; our invention will now be: described in detail: in connection with the-drawings; in which;

Figure 1 is a diagrammatic view showing the various components ,of': the system' andzthe manner in which they. are associated with ,one another. Theviewis, strictly diagrammatic, and. theexact location. of the parts. shown; therein are not toibe taken as to position which these parts wouldoccupy in an actual installation of the-systemeon an aircraft.

Figure.2..is: a detailed .view of the three-way valve whichis shown partially; in cross-section for the purpose of: clearly illustrating the exact details of its construction.

Inasmuch Figure 3 is a detailed view of the operator for the valve which is located on the dashboard of the aircraft. This view is shown partiallyin cross-section so as to reveal the construction of parts located in the interior of the device.

In Figure 1 is shown a fuel system for a fourengined aircraft which system embodies the principles of our invention. In this view the four engines are not shown but only the carburetors I6, I2, [4 and I6 which are mounted on each of the engines. Each of these carburetors is supplied with fuel under pressure by the four engine pumps I8, fuel strainers 26 being provided ahead of each of the pumps for the purpose of removing any impurities present in the fuel. Fuel is supplied to these strainers from a plurality of tanks which are preferably located in the wings of the aircraft, the tank 22 supplying fuel to the carburetor I6 of the first ngine and the tanks 24 and 26 supplying fuel to the carburetor I2 of the second engine. The tanks 24 and 26 are connected with one another by a short fuel line 25 so as to form essentially a single tank for the a carburetor I2. It is necessary that the two tanks 24 and 26 be used in place of a single tank similar to 22 because of the limited space available within the aircraft wing. For the same reason tanks 28 and 36, which are joined by a short line 29, take the place of a single tank for the carburetor I 4. A tank 32 forms the source of supply for the carburetor I6. Two reserve fuel tanks 34, which may or may not be present in the aircraft, are tied together by a short fuel line 35 so as to form a single source of fuel reserve. Each of the tanks 22 to 34 is provided with an air vent 36 located in the top thereof. A fuel line 31 leads fromthe bottom of each tank to the intake side of a booster pump 38. While some of these pumps are shown in the figure as being above the bottom of the levelof the tanks, it is to be understood that this was done in order to conserve space in the drawing and that in an actual installation each of the pumps would be located below the bottom level of the tank from which it draws fuel. These pumps are preferably driven by individual electric motors with provision made for controlling their operation from the pilots cabin. The pumps themselves are of the centrifugal type since this form of pump will permit fuel to flow through it even though it is not operating. A fuel line 39 conveys the fuel from the exhaust side of each of the booster pumps to one of the ports of a three-way valve, these valves being designated as 46, 42, 44 and 46 in the drawing. To a second port of each of the valves is connected a short fuel line 41 which conveys the fuel to each of the strainers 26 after which it proceeds through the pumps and caliburetors to each of the four engines. A cross-feed fuel line 48 is communicatively connected to a third port of each of the three-way valves, a T fitting 56 being utilized to connect the cross-feed line to each of the valves 42 and 44. A simple cut-off valve 52 is interposed between thebooster pump38 of the reserve source 34 and the cross-feed line 48. A cross 54 serves to connect the line from the reserve source to the cross-feed line 48. A fuel pressure gauge 56 is connected with one of the legs of the cross 54 in order to indicate at all times the pressure of the fuel in the cross-feed line 48. Each of the four valves 46, 42, 44 and 46 is provided with a hydraulic line 58 extending to an operator 66 located on the dashboard 62 of the aircraft. Each of the operators 66 is provided with an elongated handl 64 which serves both to ac- 6 tuate the operator mechanism and also to in dicate the position of each of the valves 46, 42; 44 and 46.. i

Where the system is to be installed on military aircraft it is desirable that the fuel tanks and fuel lines beof bullet-proof construction though the type of construction used in no way alters the principle of our invention.

Figure 2 is a detailed view of the valve 46 which is interposed between the tank 22 and the carburetor I6. This valve, which is typical of all the valves 46, 42, 44 and 46, consists of a valve body 66 which is provided with three outlet legs, 68, 16, and I2. The fuel line 41 leading to the carburetor and engine is connected to the leg 68; the fuel line 39 leading from the tank to the valve is connected to the leg I6; and the cross-feed line 48 is connected to the leg 12. The legs 68 and I2 are cast integral with the valve body 66, the latter leg communicating with an annular wall I4 which is located in the interior of the body and which projects from the end wall 16 of the body 66. The right-hand edge of the wall 14 is beveled off to form a valve seat I8. The leg 16 is integral with an end housing 86 which is adapted to screw into, and tightly seal against the open end -of the body 66. This end cap is provided with a beveled annular surface 82 forming a second valve seat which lies directly in line with the valve seat 18.

On the left-hand end of the body 66.is screwed a housing 84 which is tightly sealed against the end wall 16 by means of gaskets 86. 'Ihecuter end of the housing 84 is provided with a tapped hole 88 for receiving a fluid fitting 98 mounted on the end of a hydraulic line 58. The body 66 is provided with a guide-bearing 92 which 'slidably receives the valve stem 94. The left-hand end of the valve stem is provided with a flange 96 to which is soldered one end of a Sylphon bellows 98. The other end of the bellows is soldered to a flange I66 formed on the housing 84 thus forming a fluid tight chamber between the outer surface of the bellows and the" interior surface of the housing with the exception of the opening for the hydraulic line 58. A compression spring I62 is located within the Sylphon bellows and has one end bearing against the flange 86 and the other end bearing against the end wall 16. This spring tends to constantly extend the bellows so as to move the valve stem 94 into its left-most position. A small hole I64 is drilled through the end wall I6 so as to provide communication between the inside of the bellows and the interior of the valve body. The right-hand end of the valve stem 94 is provided with screw threads I66 by means of which a valve head composed of two sealing washers I68 and three supporting washers IIII may be secured to the right-hand end of the valve stem. The washers I08 may be of any suitable sealing material such as rubber, rubber substitute, leather, etc. The use of a rubber substitute such as neoprene is preferable since this material is not affected by gasoline. The valve stem 94 is adapted to be moved back and forth within the valve body by means of fluid pressure in the hydraulic line 58 and in the housing 84. When the pressure on the hydraulic fluid contained in the line and housing is released the valve will be free to move toward the left under the influence of the spring I62 to cause the valve head to press against the valve seat I8 and thus seal off the cross-feed port from the interior of the valve body. 'Fuel entering the valve body through the line 39 from'the fuel tank will be free to flow through the interior of the valve body and out through theline 4-1 'totthecarburetor It, The 'cidSS-feed-line 118;: however, will beefiectively sealed off from the tank-to-engine fuel line.. Upon moving-a predetermined amountef hydrauliczfliiid into: thehodsing from the line a',jthe bellows 9'8 valve head will be m'o'vedito its intermediate p'osiition as shown in Figure 2. a'ir or fuelFW'rthin the interior of the Sylphohbellotvs will hosiermitted to escape through thehole' zl Mso -'as-'not :to; interfere with the, compressing thereof. with the \valve-ihead in its central: orfintermediateiposie tion allthree legs ofthev'alve communicate with;

the interior of thesvailve'body 1G6 and =fue1. from the tank line 39 -will'be free-tofiow'through'hothe the engine'linefi andalso thexcrds$feed line 48.- Upon moving {an 7 additional? amount of "fiuid' into the housing from the *line, the bellowsand spring" will be compressed still f-urtherasand the valve head will be pressed agains'twtheseat-82130 as "to seal off-the leg :and-the tank-line 39 from the interl0r"of-the valve-body The legs "Hhand 68 will-now: be in communication-with one another and fuel will be. ires to, flow/from the. eros's-fee'dv line 48 through the valve and :out'into the engine line 41.

The :operator 60: which serves; to-control the position ofthe valve: Wis-shown in-detail iniFig'-' ure 3. Thisdevice has'an operating handle 54 6f elliptical-shape which is f asten'ed to X one end 'o'f a sleeve 112', This: sleeve-"is slidabiy received; in 'a guide-bearing. l-3' formed-in one end 'of the o'p erator bod-y- H4; In-the-sleeve is cutwaii'elieal' groove-l l-6 which cooperates-with the projecting end I H of a screw '1 I S- mOun-te'd in the body 'I I 4. Thus" as the handle GQ-is'mtatedthesleeve l -l .Ziwill vided in the end of sleeve 11-2 The right-hand end of'the bellows-J24 issoldered-tothe =face Man 1 endhousing I 21 i which is'screwedinto the open end of the body H 4. The ports I 2-8--drilled in the housing 121 asshown in Figure 3,- -serve to=establishcommunication between the interior" of the bel lows andthe inter-iorof a- -cylinder. ltd-fastenedand sealed-tothe-housing l2-'l;.- -Afiller=-tube-l3l extends within the cylinder asshown, this tube being screwed intothehousingat. 34;- The-hydraulic line 58;is connected to the right-hand-end of the filler tube by meanse -a fluid fittin 1- Communication between the line and the-interiorof thenllows l;2 4 is thusestablis hed by means of the filler. tube l 32; the cylinder" i 3d and the pol-ts I23 Thelefthand endof the cylinder l39 islprovlde d with altapped-hole I38 to-accommodate-a filling "plug. After thesystem-has beenfilled-with hydraulic fiuid'by means of thehole l38-,--rotation of the handle-B4 of the operator willtenol-to either compressor expandthe bellows 1 24; depending-on the di'rection of rotationo'f-the handle, and thus either'force thefluicl contained in the bellowslfl into the line 58 or withdraw-the same from the line as the-case may be. E'acli-t-endof the helical groove'l'i Bis provided with a straight portion as is also the'ce'ntral-part oilthe groove. vTheSestIaight portions serveto determinethe 'threepositions 6f the valve head of the valve '49: The compression spring I25, which resiliently holdsthe head of the bdlt"le0tim .position against the flange in righthand endof. the sleeveg-serve's to compensate for any expansioniofathevhydraulic fluid contained in the'remote contro'lSystem.- Thusif the fluid-expands and-causes thevalve head: to contact the valve seat 82-before the handle 64 has'reached its limit ofmoveriient, the spring, I25 w-i-llyyieldto permit the sleeve H 2 to continue its m'ovement in-to thexoperator body without, causing corresponding movement-of the bolt-[-20 iand =the:head 1 22 The face ofthe handle 64' is provided with anzindex 'li'ne which cooperates with an indicator dial'on the -'dashboard-;62 ofthe aircraft so as indicate -tothe pilot the position-occupied'by -the fuel control; valve 40.; This dial; is,- ofcourse, marked with three positions corresponding to the three positionsoccupied'by the operator handle and also by the valve headxsuitable legends being providedon-the dial so-indicate to the pilot-the manner in which the duel-is flowing through the valveat any-given instant,

Severalsample types of operation which may be performed .withcursystem-will now be given Problem- 1'.To -deliver fuel from one of the fueltanks-to-all-tour of-the-engines. 7

To cause fuel-from the tank 2 2 to be, delivered to the four engines of the aircraft the .pilot or copilot, as the case may be moves valve Ill-toits intermediate position; by means, of the "operator handle -6 l-oont1ol1-lng the same This will then permit the-iuel-from the tank 2 2 t'o flow bo'thto the carburetor f0 and=also into the cross-feed line 68-. By means of the other-operator handles 641 the-valves 42', 4 4" and-16am then positioned with the valve head-contacting the valv'eseat 82 so as topermit' fuel to flow from the cross-feed line 4 8 intothelinesll leadingvtothe carburetors I2, II and 16; At the sametime the threeftank lines e e cwill-be blocked o'iT so as-to isolate the three'remain'ing tanks from the remainder of the system; Thus 'theffueledelivered from the tank 22 into the 'crdss-feed linelawillbe delivered-to the three carburetors IZQI'A and-[6 in addition to the vcarburetorv associated with thetan'k '22.

The operation or hon-operation of "the booster pumps-38fisiminat'erial in this particulars-problem provided the aircraft is notflying 'at'an excessive altitudegsay 12000 "feet-OI above. If the craft is operatihiabove lZLO'O'O fee-tit will be necessary-to have the "booster 'pll'lfi'p' BIS'SOCi atEd With 'the'tank iha'ri operative cbn'd'ition'in' order 'to lift the me'ltup t'othefouiengine'puinpS IlB.

'Proble'm' 2.'--To"de'1iver fu'el from the reserve tanks 3H0 all four or the engines.

' pumps" EB 'iS-"imI'nateI-ial unless the aircraft is flyingr a't anexcessive altitude. If thisis the case it willbe-necessary that the booster p'ump'38 associated with the reserve tanks 34 be operating :30

as'to lift the 'fiie1up tothe fdurenginapumps l-l 8.

9 Problem 3.-To transfer fuel from one tankto another tank. 7 V v I If it is desired that fuel from the tank 22 be transferred to the tank 32, the operator handle 64 for the valve 46 is moved so as to place the valve in its intermediate position. This will permit the fuel from the tank 22 to flow into the valve and out through the engine line 41 and the cross-feed line 48. The operator handle for the valve 46 is likewise moved so as to position the valve in its intermediate position so as to establish communication between all three of the fuel lines entering this valve. The booster pump 38, associated with the tank 32, is then silenced and the booster pump of the tank 22 rendered operative. Fuel from the tank 22 will thus be supplied under pressure both to its own engine and also to the cross-feed line. From the cross-feed line fuel-will flow through the valve 46 to the carburetor l and also to the tank 32. Since the booster pump of the tank 32 is stopped, the fuel will have no difficulty in passing through this pump in the reverse direction. Thus, as a result of the pressure developed by the pump of the tank 22, fuel therefrom will be forced through the cross-feed line and into the tank 32. During this operation the engines associated with the carburetors i2 and I4 may continueto operate in the normal manner with fuel being supplied directly from their associated tanks through the valves 42 and 44 and into the engine lines 41. To accomplish this the operator handles 64 for the valves 42 and 44 are moved so as to seat the heads of these two valves against the seats I8, thus permitting a direct flow of fuel from the tank lines 39 to the engine lines 41, the cross-feed 1ine 48'being sealed off in each case.

Problem 4.-To transfer fuel from-the reserve tanks 34 to one of the enginetanks. 7

If it is desired' that fuel'from the reserve tanks 34 be transferred into the tank 22 the operator handle 64 for the valve 40 is moved so as to place this valve in its intermediate position. The booster pump 38 associated with the tank 22 is then stopped and the booster pump associated with the reserve tank 34 is set into operation after opening the valve 52. Thus fuel'will be delivered from the reserve tanks intothe crossfeed line under pressure so as to cause the fuel to flow through the valve 40 and into the tank 22. At the same time the engineassociated with the tank 22 will be supplied with fuel through the line 41, it being recalled that the valve 4!! is in its intermediate position with all three of thefuel lines entering the valve in communication with one another. The remaining three engines may be supplied with fuel from their respective tanks while this fuel transfer operatio is being carried out by so moving the operator handles 64 for the three valves 42, 44 and 46 asto seat the valve heads against the valve seats 18, thus permitting a direct flow of fuel throughthe valves from the tank lines 39 to the engine lines 4". ,7 During fuel transfer operations thefuel pressure gauge 56 connected with the cross-feed line will be operative to indicate thepressur of'the fuel in the cross-feed line and thus indicate to the pilot that the transferring operation is proceeding satisfactorily. 1

Th examples set out above are typica1 of crossfeed and transfer operations which may heparformed with our improved fuel system. It willbe evident, however, that many variations of these operations maybe carried out with various setl0 tings of the valves 40 to 46 and selective operation or non-operation of the different booster pumps 38. Since it would be impossible within the space of this description tobring out all of the possible permutations available with our system, only the four basic types of operation have been described in detail. It will be evident, however, from the above description of our improved system that, by a simple manipulation of the appropriate operator handle 64 on the dashboard of the aircraft, the pilot may quickly and readily adjust any one of the three wayf valves to the desired position. By means of these valves the cross-feed of fuel between engines is controlled as is also the transfer of fuel from one tank to another. In transferring fuel between tanks it is necessary to stop the booster pumpof the tank into which fuel is being pumped, and, inasmuch as these pumps are preferably driven by electric motors, it is a simple matter to provide suitable starting and stopping switches for these motors on the dashboard of the aircraft. Thus all controls are placed within easy reach of the pilot and the flow of fuel through the system maybe readily and quickly controlled by manipulation of the dashboard controls. 1 It is to be understood that the particular embodiment of our invention, which has been described aboveis for purposes of illustration only and that our invention is not to be construed as limited to the arrangement herein disclosed. The extentof our invention is rather to be determined by the'scop'e of the appended claims which follow. Whatwe claim as new ancldesire to secure by Letters Patent is: V p p 5 l. A'fuel supply system for multiengined aircraft'oomprising a plurality of fuel outlet means, a fuel reservoir mean-s associated with each of said outlet means, an individual conduit com municatively connecting each of said outlet means with'its associated reservoir means, a valve interposed in eachof said conduits, and a cross-feed conduit communicativelyconnected with each of said valves, said valves each having a selectively settable control member for enabling fuel to be delivered from any selected reservoir means to any selected outlet means. A 2. A fuel supply system for multiengined aircraft comprising ajplurality offuel outlet means, a fuel reservoir means associated with each of said outlet means, an individual conduit communicativelyconnecting each of said outlet means with itsassociated reservoir means, a selector valve interposedin each of said conduits, each of said valves having a control member settable to an one of a plurality of positions, a cross-feed conduit communicatively connected with each of said valves, and means for individually controlling the setting of each of said control members so as to enablefuel to be delivered from any selected reservoir means to any selected outlet means.

v3. A fuel supplysystem for multiengined aircraft comprising a plurality of fuel outlet means, a fuel reservoir means associated with each of said outlet means, "an individual, conduit communicativelyeonnecting each of said outlet means with its associated reservoir means, a multiway valvelinterposed in each of said conduits, each of saidvalves having a control member capable of beingmoved into any one of a plurality of positions. a cross-feed conduit communicatively connected with each of said valves, and means for individually controlling the position of each of said control members, so as to enable fuel to be 11 delivered from any selected reservoirwmeans to any. selected outlet ,means,

4. r A fool. supply'esystem .for multiengined aircraft --comprising. aplurality of ,tuelsoutlet means a fuel reservoir vmean-s: associated with-reach of said outlet. means;. and a valve inter-posedsbetween each outlet rmeans and its associated reservoir means; each of said valvescomprisinaamultiport valve body havingione port: communicatively connected with the :outlet means,;arsecond port: communicatively connectedwithzthe-reservoir means, and a-third port communicatively connected-with a corresponding ;port of -.eac-h otrtherother. of; said valves,.-and-a positionable selectormeans fer controlling the-flowot fuelithroug-hsaid valve body and between .said ports whereby :fnel imay' be-delivered from anvzselected reservoir means to any selectedoutlet means;

5.- A fuel supply system ior: multiengined :aircraft comprising :a plural-itvof :fuel outletameans; a-fuel reservoir means associated with seaoh-r 'of said outlet means; anma valveinterposedi between each outlet means and its associated: reservoir means, each of said valvesebeing' comprised of a multiportvalve body,.-one port of whicnis'communicatively connected with said outletmea-ns, a second part of which is-communicatively connected with said reservoir means-ands third port of which is communicatively' eonnected with a corresponding port of themother of-said valve bodies, anda selector means movable to any one of three positions, said means in one position serving to establish communication between :said one port and saidasecondport, inma secondposition serving to establish communication :between all :three of said ports ,andvin a third position serving to establish communication between said one port and said-third port whereby withsthe selector means of aone'zof said valvesoccupying its second position and with the selector means of other of :said valves occupying their-third positions,v iuel may flow from the reservoir ofusaid one valveto the outlet means. both of said one valve and also .of. said other valves.

6. A fuelsupply system for multienginedaircraft comprising a plurality of fuel outlet means a fuel reservoir meanstassociated with eachof said outlet means; and avalve interposedbetween each outlet means and its-associated reservoir means, each of said valvesbeingcomprised of av multipo-rt valve bod-y, one port of WhiGhdiS- communicatively connected with said outlet means, a second portof which rcommunicatively con.- nected with said reservoir means anda third port of which is communicatively connected with ,a corresponding ,port of the other of said valve bodies, and ,a selector means, movable to any one of three positions, said means in one position serving to establish communication between ,said one port and said second port in-a second position serving to establish communication between all three of said ports, and in a third position serving to establish communicationbetween said one port and said third port whereby. with the selectormeans of certain .ones of said valves ,occupying their second po'sitions and the selector means of certain others of said valves occupying their third positions, fuel will-be-permitted to flow from the reservoirs of said certain ones of said valves to theou-tle't means thereof and also to the outlet means of said certain others of said valves.

7. In a fuel supplysystem for multiengined aircraft comprising a plurality of fuel outlet means, a fuel reservoir means associated with each of said outlet means, a selectively operablecentrifugal pump located adjacent, to each of said reservoir means and communicativelyeom nected therewith for supplying fuel under pressure tosaidoutlet means; each-of said pumps being characterized by-jits ability topass fuel when .inoperat'iveya conduitrcommunicatively connecting each-of-said pumps with its-associated outlet means, a th'reerway valve, interposed in each of said- GOHdllitSqbBtWEGI-l said pump and said, outlet means, 'each of said valves being provided with a controlmember-settable toone of a pluralityofpositions a cross-feed conduit communicatively connected with each of: said valves, and means-for individually controlling the setting of the valve control members so as to enable the Pu p associated with any selected reservoir means, whenrendered operative, to withdraw fuel from. that reservoir means and deliver it to any of the remaining reservoir-means whose associated pumps have beerrrendered inoperative.

-8. .A. fuel supplysystem for aircraft comprising a plurality-of fuel outlet means, a fuel reservoir means. associated-with each-of said outlet means,

an individualeconduit communicatively connect- .ing: each -of..said outlet means with its associated reservoir means a multiway valve interposed in said conduit; said valve having acontrol member capable of:- being moved into anyone of a plurality-or positions; a selectivelyoperablecentrifugal pump interposed each: of said oonduits betweensaid valve and said reservoir means, said pump-tbeing-characterized by itsability to pass fuel when: inoperative, a cross-feed; conduit communicatively connected with each of said valves, .and means for individuallyrcontrolling the position of the-control member of each of said valves so as to enable fuel to be pumped from'any'selected reservoir means whose associated pump has been rendered operative and delivered to any other selected reservoir means whose associated pumphas been renderedinoperativeat the same time thatfuel is beingdelivered to the outlet means associated with said selected reservoir means. r

9 A iuel supply system for multiengined aircraft comprising a plurality of: fuel outlet means; afuelreservoir means associated with each of said 'outletmeans; a selectively operable pump interposed-between eachoutlet means and its associated reservoir means, said pump being communicativel-y connected with said reservoir means and being characterized by its-ability to pass fuel when inoperative; andavalve interposed between each of said pumps and its'respective outlet means, each of said valves being comprised of a multiport valve body, one port of which is communicatively connected with said' outlet means, a second port :of' Whichis-communicatively connected with said.- :pump and a third port of which is communicatively connected with a corresponding port of the other of said valve bodies, and a selector means :movab'le to :any one of three positions, said means in one position serving to establish communication between said one port and said second port, in another position serving to establishcommunication(between all three of said ports, and in still a further 'position serving to establish communication between said one port and said third port whereby, upon effecting a proper setting of the selector means-of said valves, fuel may lbs-transferred from any selected reser voir means whose associated pumphas been rendered operative to any of the remaining reservoir means whose associated pump has been rendered inoperative and delivered from said-selected reser- 13 voir means to the outlet means associated with said selected and said remaining reservoir means and also to any other desired outlet means,

10. A fuel supply system for multiengined aircraft comprising a plurality of fuel outlet means, a fuel reservoir means associated with each of said outlet means, an individual conduit communicatively connecting each of said reservoir means with its associated outlet means, a multiway valve interposed in each of said conduits, said valve having a control member settable to any one of a plurality of positions, a cross-feed conduit communicatively connected with each of said valves, a reserve fuel reservoir means, a separate conduit communicatively connecting said last-named means with said cross-feed conduit, and a shutoff valve interposed in said separate conduit for isolating said reserve fuel reservoir means from said cross-feed conduit whereby, upon proper manipulation of said control members, fuel may be delivered from any selected reservoir means to any selected outlet means.

11. A fuel supply system for multiengined aircraft comprising a plurality of fuel outlet means, a fuel reservoir means associated with each of said outlet means, an individual conduit communicatively connecting each of said reservoir means with its associated outlet means, a multiway valve and a centrifugal pump interposed in each of said conduits, said valve being located between said pump and said outlet means and being provided with a, control member settable to any one of a plurality of positions, a cross-feed conduit communicatively connected with each of said valves, a reserve fuel reservoir means, a separate conduit communicatively connecting said last-named means with said cross-feed conduit, and a shut-off valve and a centrifugal pump interposed in said separate conduit, each of said aforementioned pumps being characterized by its ability to pass fuel in either direction when rendered inoperative whereby, upon proper setting of said control members, fuel may be transferred from any selected reservoir means whose associated pump has been rendered operative to any of the remaining reservoir means wh'ose associated pump has been rendered inoperative and simultaneously delivered to any one or more of said outlet means.

12. A fuel supply system for multiengined aircraft comprising a plurality of fuel outlet means, a fuel reservoir means associated with each of said outlet means, an individual conduit communicatively connecting each of said outlet means with its associated reservoir means, a valve interposed in each of said conduits, each of said valves having a control member settable to any one of a plurality of positions, a motor driven pump interposed in said conduit between said valve and said reservoir means, each of said pumps being of the type which will permit fuel to flow freely therethrough in either direction when its driving motor is rendered inoperative, and a cross-feed conduit communicatively connected with each of said valves, whereby, upon proper manipulation of said control members, the pump associated with any selected reservoir means whose driving motor has been rendered operative may withdraw fuel from said selected reservoir means and deliver it to any of the remaining reservoir means whose associated pump motors have been rendered inoperative and also to any one or more selected outlet means.

13. A fuel supply system for multiengined aircraft comprising a plurality of fuel outlet means,

a fuel reservoir means associated with each of said outlet means, an individual conduit communicatively connecting each of said outlet means with its associated reservoir means, a multiport valve interposed in each of said conduits, each of said Valves having a control member settable to any one of a plurality of positions, a cross-feed conduit communicatively connected with one of the ports of each of said valves, a reserve fuel reservoir means, an individual conduit communicatively connecting said reserve fuel reserve means with said cross-feed conduit, a shut-off valve in said last named conduit, and a selectively operable pump interposed in each of said individual conduits between said reservoir means and said valves, each of said pumps being characterized by its ability to pass fuel freely in either direction when rendered inoperative, whereby, upon proper manipulation of said control members, fuel may be transferred from any selected reservoir means whose pump has been rendered operative to any of the remaining reservoir means whose pumps have been rendered inoperative.

14. A fuel supply system for multiengined aircraft comprising a plurality of fuel outlet means, a fuel reservoir means associated with each of said outlet means, an individual conduit communicatively connecting each of said outlet means with its associated reservoir means, a valve interposed in each of said conduits, each of said valves having a control member settable to any one of a plurality of positions, a cross-feed conduit communicatively connected with each of said valves, a reserve fuel reservoir means, and a shutoif valve communicatively connecting said reserve fuel reservoir means with said cross-feed conduit, said control members being individually settable so as to enable fuel to be transferred from any selected reservoir means to any selected outlet means.

15. A fuel supply system for multiengined aircraft comprising a plurality of fuel outlet means; a fuel reservoir means associated with each of said outlet means; and a valve interposed between each outlet means and its associated reservoir means, each of said valves comprising a multi port valve body having one port communicatively connected with the outlet means, a second port communicatively connected with the reservoir means, and a third port communicatively connected with a corresponding port of each of the other of said valves, and the valves having a positionable selector means for each valve for controlling the flow of fuel through said valve body and between said ports whereby fuel may be delivered from any selected reservoir means to any selected outlet means.

RALPH E. GREY. EDWARD M. GAVIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 312,158 Peeney Feb. 10, 1885 1,329,997 Page Feb. 3, 1920 1,532,326 Lent Apr. 7, 1925 1,776,877 Yonkese Sept. 30, 1930 1,889,517 Roessler Nov. 29, 1932 2,024,133 Harding Feb, 23, 1937 2,170,136 Gavin Aug. 22, 1936 2,243,594 De Voe et :al May 27, 1941 2,268,957 Muselier Jan. 6, 1942 

